1. Field of the Invention
The present invention relates generally to an electrical, optical, or electro-optical connector for use in harsh environments such as subsea environments, and is particularly concerned with the seal assembly in receptacle and plug units of such connectors for closing and sealing contact chambers in the mating plug and receptacle units when de-mated, and for allowing communication between the two units on mating to allow first contacts in one unit to extend through or past the seals into other unit for contact with second contacts in the other unit, while still sealing the contacts from the external environment.
2. Related Art
There are many types of connectors for making electrical and fiber-optic cable connections in hostile environments. One type includes connectors for undersea mating and de-mating. Such underwater connectors typically comprise a plug unit containing one or more contact probes and a receptacle unit containing an equivalent number of receptacle contacts or junctions for engagement with the contact probes, which extend into the receptacle unit when the units are connected together. Typically, the contacts or junctions are contained in a sealed chamber containing dielectric fluid, and the probes enter the chamber via one or more normally sealed openings. One major problem in designing such units is the provision of seals which adequately exclude sea water from the contact chamber even after repeated mating and de-mating, and also prevent dielectric fluid from leaking out of the chamber.
A number of different sealing mechanisms have been proposed in the past for achieving this objective. One such sealing mechanism has an opening into the contact chamber which comprises an elastomeric tubular entrance surrounded by an elastomeric sphincter which pinches the entrance closed upon itself when the plug and receptacle units are in an unmated condition. In the mated condition, the sphincter pinches against the entering probe to form a seal. Although this type of seal is successful in some cases, it does have disadvantages. One disadvantage is that this seal does not work well under all hostile conditions. Another disadvantage is that such seals tend to lose their “memory” after repeated mating and de-mating, so that they may fail to close completely, or may not close quickly enough to isolate the chamber from the surrounding environment when the units are de-mated. Another type of known seal mechanism comprises a piston which moves axially into the seal opening as the units are de-mated.
Underwater electro-optical connectors are described in U.S. Pat. Nos. 4,616,900 and 4,666,242 of Cairns. In U.S. Pat. No. 4,666,242, the male and female connector units are both oil filled and pressure balanced. This device utilizes a penetrable seal element having an opening which pinches closed when the units are separated. Other known fiber-optic connectors have similar seals which are not suitable for use under some conditions and may tend to lose effectiveness after repeated mating and de-mating.
Some prior seal mechanisms are not completely effective in providing repeatable, reliable optical and electrical connections in adverse environments while maintaining electrical or optical contacts or terminals in isolated chambers at all times. Optical connectors can be expensive and generally require complicated means for terminating the connector elements or junctions to the cables they are intended to connect.
Harsh environment or underwater connectors are known in which dielectric fluid filled contact chambers in the plug and receptacle units are sealed at the front ends of the connectors by rotating seal elements which have openings aligned with corresponding openings into the contact chamber or chambers in the mated condition and offset from the openings in the unmated condition, for example as described in U.S. Pat. No. 5,685,727 of Cairns.